1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
|
%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2008-2009. All Rights Reserved.
%%
%% The contents of this file are subject to the Erlang Public License,
%% Version 1.1, (the "License"); you may not use this file except in
%% compliance with the License. You should have received a copy of the
%% Erlang Public License along with this software. If not, it can be
%% retrieved online at http://www.erlang.org/.
%%
%% Software distributed under the License is distributed on an "AS IS"
%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
%% the License for the specific language governing rights and limitations
%% under the License.
%%
%% %CopyrightEnd%
%%
%%
%%% Description: Reading and writing of PEM type encoded files.
%% PEM encoded files have the following structure:
%%
%% <text>
%% -----BEGIN SOMETHING-----<CR><LF>
%% <Base64 encoding line><CR><LF>
%% <Base64 encoding line><CR><LF>
%% ...
%% -----END SOMETHING-----<CR><LF>
%% <text>
%%
%% A file can contain several BEGIN/END blocks. Text lines between
%% blocks are ignored.
%%
%% The encoding is divided into lines separated by <NL>, and each line
%% is precisely 64 characters long (excluding the <NL> characters,
%% except the last line which 64 characters long or shorter. <NL> may
%% follow the last line.
-module(pubkey_pem).
-export([read_file/1, read_file/2, write_file/2, decode/2]).
-export([decode_key/2]).
-define(ENCODED_LINE_LENGTH, 64).
%%====================================================================
%% Internal application API
%%====================================================================
read_file(File) ->
read_file(File, no_passwd).
read_file(File, Passwd) ->
{ok, Bin} = file:read_file(File),
decode(Bin, Passwd).
write_file(File, Ds) ->
file:write_file(File, encode_file(Ds)).
decode_key({_Type, Bin, not_encrypted}, _) ->
Bin;
decode_key({_Type, Bin, {Chipher,Salt}}, Password) ->
decode_key(Bin, Password, Chipher, Salt).
decode(Bin, Passwd) ->
decode_file(split_bin(Bin), Passwd).
%%--------------------------------------------------------------------
%%% Internal functions
%%--------------------------------------------------------------------
split_bin(Bin) ->
split_bin(0, Bin).
split_bin(N, Bin) ->
case Bin of
<<Line:N/binary, "\r\n", Rest/binary>> ->
[Line | split_bin(0, Rest)];
<<Line:N/binary, "\n", Rest/binary>> ->
[Line | split_bin(0, Rest)];
<<Line:N/binary>> ->
[Line];
_ ->
split_bin(N+1, Bin)
end.
decode_file(Bin, Passwd) ->
decode_file(Bin, [], [Passwd]).
decode_file([<<"-----BEGIN CERTIFICATE REQUEST-----", _/binary>>|Rest], Ens, Info) ->
decode_file2(Rest, [], Ens, cert_req, Info);
decode_file([<<"-----BEGIN CERTIFICATE-----", _/binary>>|Rest], Ens, Info) ->
decode_file2(Rest, [], Ens, cert, Info);
decode_file([<<"-----BEGIN RSA PRIVATE KEY-----", _/binary>>|Rest], Ens, Info) ->
decode_file2(Rest, [], Ens, rsa_private_key, Info);
decode_file([<<"-----BEGIN DSA PRIVATE KEY-----", _/binary>>|Rest], Ens, Info) ->
decode_file2(Rest, [], Ens, dsa_private_key, Info);
decode_file([<<"-----BEGIN DH PARAMETERS-----", _/binary>>|Rest], Ens, Info) ->
decode_file2(Rest, [], Ens, dh_params, Info);
decode_file([_|Rest], Ens, Info) ->
decode_file(Rest, Ens, Info);
decode_file([], Ens, _Info) ->
{ok, lists:reverse(Ens)}.
decode_file2([<<"Proc-Type: 4,ENCRYPTED", _/binary>>| Rest0], RLs, Ens, Tag, Info0) ->
[InfoLine|Rest] = Rest0,
Info = dek_info(InfoLine, Info0),
decode_file2(Rest, RLs, Ens, Tag, Info);
decode_file2([<<"-----END", _/binary>>| Rest], RLs, Ens, Tag, Info0) ->
Cs = erlang:iolist_to_binary(lists:reverse(RLs)),
Bin = base64:mime_decode(Cs),
case Info0 of
[Password, Cipher, SaltHex | Info1] ->
Salt = unhex(SaltHex),
Enc = {Cipher, Salt},
Decoded = decode_key(Bin, Password, Cipher, Salt),
decode_file(Rest, [{Tag, Decoded, Enc}| Ens], Info1);
_ ->
decode_file(Rest, [{Tag, Bin, not_encrypted}| Ens], Info0)
end;
decode_file2([L|Rest], RLs, Ens, Tag, Info0) ->
decode_file2(Rest, [L|RLs], Ens, Tag, Info0);
decode_file2([], _, Ens, _, _) ->
{ok, lists:reverse(Ens)}.
%% TODO Support same as decode_file
encode_file(Ds) ->
lists:map(
fun({cert, Bin}) ->
%% PKIX (X.509)
["-----BEGIN CERTIFICATE-----\n",
b64encode_and_split(Bin),
"-----END CERTIFICATE-----\n\n"];
({cert_req, Bin}) ->
%% PKCS#10
["-----BEGIN CERTIFICATE REQUEST-----\n",
b64encode_and_split(Bin),
"-----END CERTIFICATE REQUEST-----\n\n"];
({rsa_private_key, Bin}) ->
%% PKCS#?
["XXX Following key assumed not encrypted\n",
"-----BEGIN RSA PRIVATE KEY-----\n",
b64encode_and_split(Bin),
"-----END RSA PRIVATE KEY-----\n\n"]
end, Ds).
dek_info(Line0, Info) ->
Line = binary_to_list(Line0),
[_, DekInfo0] = string:tokens(Line, ": "),
DekInfo1 = string:tokens(DekInfo0, ",\n"),
Info ++ DekInfo1.
unhex(S) ->
unhex(S, []).
unhex("", Acc) ->
lists:reverse(Acc);
unhex([D1, D2 | Rest], Acc) ->
unhex(Rest, [erlang:list_to_integer([D1, D2], 16) | Acc]).
decode_key(Data, no_passwd, _Alg, _Salt) ->
Data;
decode_key(Data, Password, "DES-CBC", Salt) ->
Key = password_to_key(Password, Salt, 8),
IV = Salt,
crypto:des_cbc_decrypt(Key, IV, Data);
decode_key(Data, Password, "DES-EDE3-CBC", Salt) ->
Key = password_to_key(Password, Salt, 24),
IV = Salt,
<<Key1:8/binary, Key2:8/binary, Key3:8/binary>> = Key,
crypto:des_ede3_cbc_decrypt(Key1, Key2, Key3, IV, Data).
password_to_key(Data, Salt, KeyLen) ->
<<Key:KeyLen/binary, _/binary>> =
password_to_key(<<>>, Data, Salt, KeyLen, <<>>),
Key.
password_to_key(_, _, _, Len, Acc) when Len =< 0 ->
Acc;
password_to_key(Prev, Data, Salt, Len, Acc) ->
M = crypto:md5([Prev, Data, Salt]),
password_to_key(M, Data, Salt, Len - size(M), <<Acc/binary, M/binary>>).
b64encode_and_split(Bin) ->
split_lines(base64:encode(Bin)).
split_lines(<<Text:?ENCODED_LINE_LENGTH/binary, Rest/binary>>) ->
[Text, $\n | split_lines(Rest)];
split_lines(Bin) ->
[Bin, $\n].
|
